Braking systems for the very large and heavy off-road vehicles generally include redundant systems so that in case there is a failure in the primary system, a back-up system exists for stopping the vehicle. Some of the back-up systems are rather bulky and complex and do not always provide redundancy for some of the components of the system. Some of the back-up systems rely on redundant energy sources of complex spring applied brakes.
Accordingly, an object of this invention is to provide an improved vehicle brake control system for braking which is relatively simple in construction and operation, is purely hydraulic and provides for a multiplicity of means of controlling a single set of brakes.